I have 3 tables. i'm looking to connect each table but unsure how.
I'm looking to get all the information from table 1 and from the other tables only if it matches the fields in table 1
table 1 (id, name_1, name_2, name_3, info_1, info_2
table 2 (description,info_1,otherstuff_1)
table 3 (name_1,name_2,name_3,random_1)
I have tried doing a join but feel that I was using the wrong syntax.
if done correctly. I'm hoping to get
id,name_1.table3,info_1.table2,name_2.table3
any help is appreciated
Table names appear before column names.
Try something like:
select t1.id, t3.name_1, t2.info_1, t3.name_2
from table1 t1, table2 t2, table3 t3
where t1.info_1 = t2.info_1
and t1.name_1 = t3.name_1
You can join tables by this query
select t1.id,t3.name1,t2.info_1,t3.name_2 from table1 as t1 join table2 as t2 on t1.info_1 = t2.info_1 join table3 as t3 on t1.name_1 = t3.name_1 and
t1.name_2 = t3.name_2 and t1.name_3.t3.name_3
Related
I have 2 tables:
Table1- contains PhoneNumber|Name
Table2- contains PhoneNumber|Address
I want to create Table3 with PhoneNumber|Name|Address
Table1 and Table2 may have out of order or different amount of entries, therefore table1 will act as main list.
please suggest way forward. using MySQL.
Use CREATE..SELECT with a LEFT JOIN :
CREATE TABLE Table3 AS
SELECT t1.PhoneNumber,t1.name,t2.address
FROM Table1 t1
LEFT JOIN Table2 t2
ON(t1.PhoneNumber = t2.PhoneNumber)
I need to show only results which are in Table1 and Table2 but are not in Table3. Basically, it should be something like TABLE1, Table2 except INNER JOIN between (TABLE1, Table2) and TABLE3.
Should looks like this - On left side Table1 and Table2, on right side Table3
Now I have this:
SELECT mesta_email, mesta_kod
FROM Table1
UNION ALL
SELECT mesta_email, mesta_kod
FROM Table2
// And somehow except values which are in Table3
Can somebody help me please? Thanks a lot.
There are a couple different ways to do this. I believe mysql does better with the outer join/null approach:
select t.*
from (
SELECT mesta_email, mesta_kod
FROM Table1
UNION ALL
SELECT mesta_email, mesta_kod
FROM Table2
) t left join Table3 t3 on t.mesta_email = t3.mesta_email
and t.mesta_kod = t3.mesta_kod
where t3.mesta_email is null
This assume table3 shares the same structure as the other 2 tables.
I would approach the problem almost directly as you write it, using exists and not exists:
select t1.mesta_email, t2.mesta_kod
from table1 t1
where exists (select 1
from table2 t2
where t2.mesta_email = t1.mesta_email and t2.mesta_kod = t1.mesta_kod
) and
not exists (select 1
from table3 t3
where t3.mesta_email = t1.mesta_email and t3.mesta_kod = t1.mesta_kod
);
One advantage of exists/not exists over other approaches involves duplicates. If one of the tables (say table1) has not duplicates, but the others might, there is no need to remove duplicates in the resulting data set.
I'm trying to join a different column (part_type_n (where n ranges from 1 to 54)) on Table1 with the same column (id, primary, autoinc) on Table2.
Schema:
Table1
==============
part_type_1
.
.
.
part_type_54
Table2
=============
id
I tried the obvious query (php generated, looping through n from 1 to 54), omitted repetitive stuff in ...:
SELECT * FROM Table1 JOIN Table2 on (Table1.part_type_1=Table2.id), ..., (Table1.part_type_54=Table2.id)
I receive this error:
1066 - Not unique table/alias: 'Table2'
How do I join these two tables?
You will have to join the table on it self again multiple times.
SELECT * FROM table1 t1
INNER JOIN table2 t2 on t2.Id=t1.part_type_1
INNER JOIN table2 t3 on t3.id = t1.part_type_54;
Hope this helps!
As an alternative to writing a query with 54 table aliases, you could consider joining to the table once - like so:
select ...
from Table1 t1
join Table2 t2
on t2.id in (t1.part_type_1, t1.part_type_2, ... t1.part_type_54)
It worked for me to get my required result as one row of which matches various categories all stored in one table column.
Query
SELECT cm3.*, xp.post_title,GROUP_CONCAT(DISTINCT sc.name) AS cate_list
FROM `xld_posts` xp
JOIN course_map cm0 ON cm0.course_id = xp.ID
JOIN course_map cm1 ON cm1.course_id = cm0.course_id AND cm0.id = 3
JOIN course_map cm2 ON cm2.course_id = cm1.course_id AND cm1.id = 6
JOIN course_map cm3 ON cm3.course_id = cm2.course_id AND cm2.id = 11
JOIN subject_category sc ON cm3.id = sc.id
GROUP by post_title ORDER BY post_title
Note: the categories values 3, 6, and 7 are got from form sumbit. Thus if your form has more than three or less your query should dynamically created and join each table with previous table.
:) Happy if any one felt useful.
I'm desperate with this query. I have two tables table1 and table2, tables are identical but they have different data. I'm trying to remove duplicities by columns code and manufacturer. To do that I need in final result ID from table1 ID from table2 and also columns code and manufacturer
SELECT * FROM (
SELECT id,code,manufacturer FROM table1 WHERE manufacturer = 1
UNION SELECT id,code,manufacturer FROM table2 WHERE manufacturer = 1
) AS t GROUP BY code HAVING COUNT(*) > 1
But in result i got only values from table1. It's OK but I just need to get there id from table2 too. Please can anyone give me some tips how to do this ?
You have two basic problems:
Problem 1:
You are using UNION when you should be using UNION ALL, because UNION removes duplicates!
Problem 2:
This isn't the right way to go about the problem. You should be using a simple join, not a union.
Try this:
SELECT
t1.id as table1_id,
t2.id as table2_id,
t1.code,
t1.manufacturer
FROM table1 t1
JOIN table2 t2
ON t2.code = t1.code
AND t2.manufacturer = t1.manufacturer
WHERE manufacturer = 1 -- this WHERE clause is optional
Your use of the WHERE clause is a little odd - consider removing it to get all duplicates from all manufacturers.
can u please show me how to query 3 tables using *? thanks
You need to do a join on the tables in order to get the columns of all of them.
Warning: using * to get all columns is bad practice. You should qualify (name) all the columns you need.
Here is an example:
SELECT *
FROM table1 t1
INNER JOIN table2 t2
ON t1.key2 = t2.key2
INNER JOIN table3 t3
ON t1.key3 = t3.key3
One way you probably don't like:
SELECT *
FROM table1, table2, table3
You have to give way more information.
This generates the Cartesian product of all the three tables.